1. Field of the Invention
This invention concerns a leak detector, in general. More specifically, it relates to a method and apparatus for detecting leaks in a body of liquid contained by a storage tank or the like. It makes use of detection of sound waves as generated by a leak, and it deals with a system for detecting such leak generated sound in spite of general background noise tending to mask same.
2. Description of the Prior Art
Heretofore, a noise reduction technique has been proposed in U.S. Pat. No. 3,432,765, to Gottfried, issued Mar. 11, 1969. However, that patent deals with the utilization of wide band noise in two signal-free channels equally spaced from and on opposite sides of a center channel containing a desired periodic signal to cancel the noise in the center channel. That technique includes a heterodyning of the two noise channel signals to the frequency of the center channel, and includes automatic phasing with each other and with the center channel noise. Furthermore, there is no suggestion that the technique of the Gottfried patent could be applied to sonic frequencies per se.
Consequently, it is an object of this invention to provide a system for sonic leak detection, in connection with liquid storage tanks or the like.
Another object of the invention is to provide for a sonic leak detector that is particularly applicable to liquid storage tanks or the like. It employs a technique for eliminating background noises in order to detect the sonic signals emitted by a leak.